This invention relates to segregator buckets for segregating materials of different particulate sizes, in particular material excavated by construction equipment such as excavators, backhoes, diggers, loaders and the like.
Excavated material contains particulates of varying sizes, ranging from small earth granules through to rubble and small rocks. Such excavated material is not readily reusable unless screened to give segregated materials of a more uniform size.
Various equipment is known for effecting such screening, but they all suffer from disadvantages. For example, it is known to provide so called shaker buckets provided with gaps therein for the passage therethrough of material within the bucket. However such buckets need to be shaken to effect the segregation, and this can impose considerable stress on the equipment, while the gaps in the buckets are at all times open whereby spillage on loading cannot be prevented.
An alternative bucket comprises a plurality of spaced, parallel ribs which are arranged to move to effect the segregation, but again the ribs are at all times spaced from one another whereby the bucket is always open, and have a tendency to clog in wet conditions
EP 0284 643 discloses a rotary bucket the walls of which comprise a grid or mesh through which the material to be separated can pass. However, the mesh is open at all times, and has a tendency to clog in wet conditions, while the bucket is not of sufficiently robust construction to enable digging out of material to be processed and therefore requires the provision of a stock pile of material prior to processing.
WO 9118152 discloses a bucket incorporating transverse, rotatable, bladed shafts the blades of which overlap whereby, on synchronous rotation of the shafts, soil in the bucket is processed. However the bucket is not of a robust construction and cannot dig material out, thereby needing a stock pile of material prior to use, and being for loader applications rather than excavation applications. Further, there is a strong tendency for the bladed shafts to become clogged in wet conditions.
This invention is concerned with providing a segregator bucket which overcomes the aforementioned disadvantages of the prior art, and in particular which is of relatively robust construction to enable digging as well as segregating of material, which has a substantially closed position to prevent spillage of material on loading, and which is less prone to clogging in wet conditions than heretofore.
In accordance with the present invention there is provided a segregator bucket comprising an open-fronted shell including a pair of opposed sidewalls and a rear wall, said rear wall including a plurality of curved, transversely spaced primary ribs defining spaces therebetween, characterised by a cage member mounted in the shell between the opposed sidewalls thereof and comprising a plurality of curved, transversely spaced secondary ribs defining spaces therebetween, the cage member being rotatable relative to the shell about an axis extending transversely of the shell between a loading position in which the secondary ribs are received within, substantially to close, the spaces between the primary ribs and a discharge position in which the secondary ribs are displaced from, to open, the spaces between the primary ribs.
Thus it will be appreciated that, with the cage member in its loading position, the bucket can be charged with material to be segregated without spillage therefrom, the subsequent rotation of the cage member to open the spaces between the primary ribs not only enabling the material to be discharged through said spaces, but also serving to agitate and tumble the material within the shell whereby small particulates adhering to larger particulates are dislodged therefrom and thereafter fall between the primary ribs to be discharged from the bucket. Ultimately only larger particulates unable to pass through the spaces between the primary ribs will be retained in the bucket.
Preferably the radii of curvature of the outer surfaces of the primary and secondary ribs are substantially the same, while the circumferential extent of the secondary ribs is substantially equal to the circumferential extent of the spaces between the primary ribs, typically less than 180xc2x0.
It is further preferred that the widths of the secondary ribs is just less than that of the spaces between the primary ribs whereby there is a small clearance between the primary ribs and the secondary ribs in the loading position of the cage member.
The cage member may be rotatable through 360xc2x0 within the shell in either direction, or may be arranged to oscillate therein between the loading and discharge positions to each side of the loading position.